JPH09103604A - Method for separating substance from liquid mixture by crystallization - Google Patents
Method for separating substance from liquid mixture by crystallizationInfo
- Publication number
- JPH09103604A JPH09103604A JP8259418A JP25941896A JPH09103604A JP H09103604 A JPH09103604 A JP H09103604A JP 8259418 A JP8259418 A JP 8259418A JP 25941896 A JP25941896 A JP 25941896A JP H09103604 A JPH09103604 A JP H09103604A
- Authority
- JP
- Japan
- Prior art keywords
- crystallization
- crystallizer
- crystals
- melt
- suspension
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000002425 crystallisation Methods 0.000 title claims abstract description 51
- 230000008025 crystallization Effects 0.000 title claims abstract description 49
- 239000000203 mixture Substances 0.000 title claims abstract description 26
- 238000000034 method Methods 0.000 title claims description 30
- 239000007788 liquid Substances 0.000 title claims description 17
- 239000000126 substance Substances 0.000 title claims description 13
- 239000013078 crystal Substances 0.000 claims abstract description 63
- 239000000155 melt Substances 0.000 claims abstract description 27
- 239000000725 suspension Substances 0.000 claims abstract description 24
- 238000004781 supercooling Methods 0.000 abstract description 9
- 238000001816 cooling Methods 0.000 abstract description 7
- 239000007787 solid Substances 0.000 abstract description 6
- 239000011248 coating agent Substances 0.000 abstract 1
- 238000000576 coating method Methods 0.000 abstract 1
- 238000000746 purification Methods 0.000 description 18
- 239000012071 phase Substances 0.000 description 13
- 239000012535 impurity Substances 0.000 description 10
- WHNWPMSKXPGLAX-UHFFFAOYSA-N N-Vinyl-2-pyrrolidone Chemical compound C=CN1CCCC1=O WHNWPMSKXPGLAX-UHFFFAOYSA-N 0.000 description 8
- 238000000926 separation method Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 5
- 238000001640 fractional crystallisation Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000008014 freezing Effects 0.000 description 3
- 238000007710 freezing Methods 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- 230000003068 static effect Effects 0.000 description 3
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 2
- GLUUGHFHXGJENI-UHFFFAOYSA-N Piperazine Chemical compound C1CNCCN1 GLUUGHFHXGJENI-UHFFFAOYSA-N 0.000 description 2
- MWPLVEDNUUSJAV-UHFFFAOYSA-N anthracene Chemical compound C1=CC=CC2=CC3=CC=CC=C3C=C21 MWPLVEDNUUSJAV-UHFFFAOYSA-N 0.000 description 2
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 description 2
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 description 2
- 208000028659 discharge Diseases 0.000 description 2
- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 description 2
- NAQMVNRVTILPCV-UHFFFAOYSA-N hexane-1,6-diamine Chemical compound NCCCCCCN NAQMVNRVTILPCV-UHFFFAOYSA-N 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000006911 nucleation Effects 0.000 description 2
- 238000010899 nucleation Methods 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 230000002269 spontaneous effect Effects 0.000 description 2
- 230000035900 sweating Effects 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 description 1
- 239000005711 Benzoic acid Substances 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 1
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 1
- 235000010233 benzoic acid Nutrition 0.000 description 1
- FOCAUTSVDIKZOP-UHFFFAOYSA-N chloroacetic acid Chemical compound OC(=O)CCl FOCAUTSVDIKZOP-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- DGTNSSLYPYDJGL-UHFFFAOYSA-N phenyl isocyanate Chemical compound O=C=NC1=CC=CC=C1 DGTNSSLYPYDJGL-UHFFFAOYSA-N 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- DVKJHBMWWAPEIU-UHFFFAOYSA-N toluene 2,4-diisocyanate Chemical compound CC1=CC=C(N=C=O)C=C1N=C=O DVKJHBMWWAPEIU-UHFFFAOYSA-N 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
- 239000008096 xylene Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0004—Crystallisation cooling by heat exchange
- B01D9/0013—Crystallisation cooling by heat exchange by indirect heat exchange
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0036—Crystallisation on to a bed of product crystals; Seeding
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
- C07B63/00—Purification; Separation; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/14—Purification; Separation; Use of additives by crystallisation; Purification or separation of the crystals
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Analytical Chemistry (AREA)
- Water Supply & Treatment (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、晶出により液体混
合物から物質を分離する方法に関する。FIELD OF THE INVENTION The present invention relates to a method for separating substances from a liquid mixture by crystallization.
【０００２】[0002]
【従来の技術】晶出、特に分別結晶は液体混合物を分離
するために有利に使用される熱的分離法である。晶出は
感熱性の物質、共沸混合物または低い比揮発度を有する
物質を分離するために特に有効である。Crystallization, in particular fractional crystallization, is a thermal separation method which is advantageously used for separating liquid mixtures. Crystallization is particularly effective for separating heat-sensitive substances, azeotropes or substances having a low specific volatility.
【０００３】分別結晶法は冷却した表面上の結晶の形成
または成長にもとづく。精製すべき混合物を適当な結晶
器に導入し、引き続き液相と組成が異なる固相を冷却し
た表面上で凍結する。使用される一定の割合の混合物を
凍結した後に液体の残留相を分離する。これは一般に残
留相を簡単に流出することにより行う。ドイツ特許出願
公開第２６０６３６４号明細書には、液体混合物から分
別結晶により物質を分離する方法が記載されており、こ
の方法においては、晶出帯域が常に充填されているとい
う条件で、液体混合物を間接的に冷却した晶出帯域を介
して乱流に繰り返し導入する。この方法のほかの構成は
欧州特許公告第０２７９４３９号明細書およびドイツ特
許出願公開第３７０８７０９号明細書に記載されてお
り、ここでは冷却した表面上で凍結した結晶層を精製溶
液と接触させ、こうして精製する。最後に記載した２つ
の明細書には冷却した表面上の薄い種結晶層の存在が記
載されており、これは溶融物を除去した後に先行する晶
出段階から晶出した液体の薄膜により形成される。この
種結晶層を形成するためには先行する晶出段階で結晶を
流出した後に強い過冷却が必要である。Fractional crystallization methods are based on the formation or growth of crystals on a cooled surface. The mixture to be purified is introduced into a suitable crystallizer and subsequently the solid phase, which differs in composition from the liquid phase, is frozen on a cooled surface. After freezing the proportion of the mixture used, the liquid residual phase is separated. This is generally done by simply letting out the residual phase. DE-A-2606364 describes a method for separating substances from a liquid mixture by fractional crystallization, in which the liquid mixture is kept under the condition that the crystallization zone is always filled. It is repeatedly introduced into the turbulent flow through the indirectly cooled crystallization zone. Other configurations of this method are described in EP 0279439 and DE 3708709, in which a frozen crystal layer on a cooled surface is contacted with a purification solution, thus Purify. The two last-mentioned specifications describe the presence of a thin seed layer on the cooled surface, which is formed by a thin film of liquid crystallized from the preceding crystallization stage after removal of the melt. It In order to form this seed crystal layer, strong supercooling is required after the crystals have flowed out in the preceding crystallization stage.
【０００４】ドイツ特許第１７６９１２３号明細書に
は、強い過冷却の結果として局所的晶出中心を形成する
ことにより晶出を開始しなければならないことが記載さ
れている。先行する晶出から生じる薄い液体の膜を強く
過冷却することにもとづく自発的な核形成による晶出の
開始は変更実施態様として記載されている。自発的な核
形成を特に低い冷却剤温度で行わなければならないこと
も指摘している。この場合に冷却に大量のエネルギが必
要であることが特に不利である。German Patent 1769123 states that crystallization must be initiated by forming local crystallization centers as a result of intense supercooling. Initiation of crystallization by spontaneous nucleation based on strong supercooling of a thin liquid film resulting from the preceding crystallization is described as a modified embodiment. It also points out that spontaneous nucleation must take place at particularly low coolant temperatures. It is particularly disadvantageous in this case that a large amount of energy is required for cooling.
【０００５】過冷却の欠点は結晶器全体を冷却しなけれ
ばならないことである。種結晶層が凝固した後に装置全
体を再び平衡温度に近い温度に加熱しなければならな
い、それというのも種結晶層と精製される溶融物の平衡
層との極端に大きい温度差により晶出の開始時に未調整
の結晶成長が生じるからである。晶出の前に装置を加熱
することは先行する過冷却に依存してエネルギに関して
かなり不利である。The disadvantage of supercooling is that the entire crystallizer must be cooled. After the seed crystal layer has solidified, the entire apparatus has to be heated again to a temperature close to the equilibrium temperature, because of the extremely large temperature difference between the seed crystal layer and the equilibrium layer of the melt to be refined. This is because uncontrolled crystal growth occurs at the start. Heating the device before crystallisation is a considerable energy disadvantage, depending on the preceding supercooling.
【０００６】欧州特許公告第０２１８５４５号明細書に
は、晶出の開始が特定の物質の場合に問題を生じる、す
なわち結晶形成の開始がしばしば再現できないことが指
摘される。この問題を解決するために、この明細書は晶
出装置に、晶出の開始時に液体分布を改良するために有
利には穿孔されているそらせ板を設けることを提案して
いる。この場合の欠点は、装置に関する付加的な経費の
ほかにそらせ板を冷却および加熱するために必要なエネ
ルギである。EP-A-0218545 points out that the onset of crystallization is problematic in the case of certain substances, ie the onset of crystal formation is often irreproducible. In order to solve this problem, the specification proposes that the crystalliser is provided with a baffle which is preferably perforated to improve the liquid distribution at the beginning of the crystallization. The disadvantage in this case is the energy required to cool and heat the baffle, as well as the additional expense of the device.
【０００７】[0007]
【発明が解決しようとする課題】本発明の課題は、分別
結晶により物質を分離する方法を、公知の方法と比較し
て、精製段階の複雑さ、従って精製の経済性に関する顕
著な利点が得られるように改良することであった。The object of the present invention is to compare the method of separating substances by fractional crystallization with the known methods to obtain a significant advantage with regard to the complexity of the purification step and thus the economics of the purification. Was to be improved.
【０００８】[0008]
【課題を解決するための手段】前記課題は、驚異的に
も、分離すべき混合物の溶融物または溶液およびこの溶
融物または溶液に懸濁している結晶からなる２相の種結
晶層を晶出の前に、晶出中に結晶が成長する結晶器の表
面に塗布することにより解決される。The object is surprisingly to crystallize out a two-phase seed crystal layer consisting of a melt or solution of the mixture to be separated and crystals suspended in this melt or solution. The problem is solved by applying to the surface of the crystallizer, where the crystal grows during crystallization, before.
【０００９】従って、本発明は、結晶器中で晶出により
液体混合物から物質を分離する方法に関し、この方法
は、分離すべき混合物の溶融物または溶液と、これに懸
濁している混合物の結晶とからなる懸濁液の形の２相の
種結晶層を、晶出の前に、晶出中に結晶が成長する結晶
器の表面に塗布することを特徴とする。以下に本発明の
有利な実施態様を説明する。The invention therefore relates to a method for separating substances from a liquid mixture by crystallization in a crystallizer, which method comprises the melt or solution of the mixture to be separated and the crystals of the mixture suspended therein. Before crystallization, a two-phase seed crystal layer in the form of a suspension consisting of and is applied to the surface of the crystallizer where crystals grow during crystallization. The following describes advantageous embodiments of the present invention.
【００１０】本発明により、“種結晶層（seed laye
r)”という語には懸濁液から沈殿した結晶および結晶器
表面に凝固した固形物が含まれる。According to the invention, a "seed crystal layer" is used.
The term "r)" includes crystals that have precipitated from suspension and solids that have solidified on the crystallizer surface.
【００１１】本発明は、種結晶層の晶出を開始するため
に溶融物または溶液の過冷却がもはや必要でないという
利点を有する。容易に不純物に含有され、従って精製効
果を低下する未調整の結晶成長がこうして回避される。
更に晶出の開始はすべての場合に再現可能である。更
に、懸濁した結晶を含有する溶融物または溶液が、欧州
特許公告第０２１８５４５号明細書、ドイツ特許第１７
６９１２３号明細書およびドイツ特許出願公開第３７０
８７０９号明細書に記載の単相の種結晶層より良好に結
晶器の表面を湿らせることが判明した。良好な湿潤は種
結晶層で結晶器を均一に被覆し、従って晶出におけるか
なり改良された分離効果を生じる。従って、前記の欠点
を生じる、欧州特許公告第０２１８５４５号明細書に記
載の付加的なそらせ板またはドイツ特許第１７６９１２
３号明細書に記載の溶融物および結晶器の過冷却を必要
とせずに晶出の精製効果が改良される。The invention has the advantage that supercooling of the melt or solution is no longer required to initiate the crystallization of the seed crystal layer. Uncontrolled crystal growth, which is easily contained in the impurities and thus reduces the purification effect, is thus avoided.
Furthermore, the onset of crystallization is reproducible in all cases. Furthermore, melts or solutions containing suspended crystals are described in EP 0218545, German Patent 17
69123 and German Patent Application Publication No. 370.
It has been found to wet the crystallizer surface better than the single phase seed crystal layer described in 8709. Good wetting uniformly coats the crystallizer with a seed crystal layer, thus resulting in a significantly improved separation effect in crystallization. Therefore, an additional baffle according to EP 0 218 545 or German patent 176 912 which results in the above mentioned drawbacks.
The refining effect of crystallization is improved without the need for supercooling of the melt and crystallizer described in No. 3.
【００１２】本発明の晶出法の工程はそれ自体いかなる
制限も受けない。冷却した表面に結晶を形成することに
もとづく作動形式を有する原則的にすべての結晶器を使
用することができる。本発明の方法は動的または静的工
程としてまたはこれらの２つの工程の組み合わせとして
実施することができる。静的な工程の場合は、たとえば
米国特許第３５９７１６４号明細書、欧州特許第０３２
３３７７号明細書およびフランス特許第２６６８９４６
号明細書に記載のように、液相が自由対流によってのみ
移動し、これに対して動的な工程の場合は液相を強制的
に対流させて実施する。これは、たとえばドイツ特許第
２６０６３６４号明細書に記載の完全に流動する熱伝達
装置中で強制的な流動によりまたはたとえばドイツ特許
第１７６９１２３号明細書および欧州特許公告第０２１
８５４５号明細書に記載の冷却した壁に液体の薄膜を塗
布することにより行うことができる。The process of the crystallization method of the present invention is not subject to any restrictions per se. In principle, all crystallizers having a mode of operation based on forming crystals on the cooled surface can be used. The method of the invention can be carried out as a dynamic or static process or as a combination of these two processes. In the case of a static process, for example, US Pat. No. 3,597,164, EP 032
3377 and French Patent No. 2668946
As described in the specification, the liquid phase moves only by free convection, whereas in the case of a dynamic process, the liquid phase is forced to convection. This can be done, for example, by forced flow in a fully flowing heat transfer device as described in DE 2606364 or for example DE 1769123 and EP 021.
This can be done by applying a thin film of liquid to the cooled walls described in 8545.
【００１３】本発明の方法は分離すべき物質の溶融物か
ら晶出するためおよび溶剤中で分離すべき物質の溶液か
ら晶出するための両方に使用することができ、一般に冷
却した表面に晶出できるすべての物質に適している。溶
融物からの分別結晶は技術的に特に重要である。分離に
特に適した液体混合物は融点−５０℃〜＋３００℃を有
し、使用される温度で分解せず、有利には、たとえばＮ
−ビニルピロリドン、ナフタリン、アントラセン、ビス
フェノールＡ、安息香酸、モノクロロ酢酸、アクリル
酸、メタクリル酸、ピペラジン、カプロラクタム、キシ
レン（異性体分離）、ヘキサメチレンジアミン、トルエ
ンジイソシアネート（異性体分離）およびジフェニルメ
タンジイソシアネート（メチレンジ（フェニルイソシア
ネート）、異性体分離）を含有する混合物である。The process according to the invention can be used both for crystallization from a melt of the substance to be separated and from a solution of the substance to be separated in a solvent, generally on a cooled surface. Suitable for all substances that can be released. Fractional crystals from the melt are of particular technical importance. A liquid mixture which is particularly suitable for the separation has a melting point of −50 ° C. to + 300 ° C., does not decompose at the temperatures used and is preferably N 2
-Vinylpyrrolidone, naphthalene, anthracene, bisphenol A, benzoic acid, monochloroacetic acid, acrylic acid, methacrylic acid, piperazine, caprolactam, xylene (isomer separation), hexamethylenediamine, toluene diisocyanate (isomer separation) and diphenylmethane diisocyanate (methylenedi). (Phenyl isocyanate), isomer separation).
【００１４】本発明の方法に使用される懸濁液は種々の
装置で製造することができる。本発明の有利な実施態様
においては、分離すべき混合物の溶融物または溶液から
結晶を凍結し、溶融物または溶液に導入する。有利には
結晶を、特に壁面の近くを通過する撹拌機を有する撹拌
冷却器または撹拌容器中で間接的冷却により凍結し、掻
き出し部材を用いて冷却した壁から懸濁液に搬送する。
結晶器それ自体によりまたは結晶器またはほかの装置に
設置された冷却可能な部材（たとえば冷却触針（cold f
inger）、冷却帯域または撹拌容器）により、直接溶融
物または溶液中で溶融物または溶液を冷却することによ
り結晶を製造し、この方法で懸濁液を製造することも可
能である。これは結晶を掻き出す必要がないという利点
を有する。冷却可能な部材の使用は結晶器全体を冷却す
る必要がないので有利である。結晶器中でまたは外部で
懸濁液を製造し、結晶器中の懸濁液の結晶を晶出表面に
沈殿し、ここで種結晶として作用することも可能であ
る。懸濁液の固体含量は懸濁液１ｇ当たり固体０〜６０
ｇである。The suspension used in the method of the present invention can be manufactured in various devices. In a preferred embodiment of the invention, the crystals are frozen from the melt or solution of the mixture to be separated and introduced into the melt or solution. The crystals are preferably frozen by indirect cooling, in a stirrer or stirrer with a stirrer passing especially near the wall, and conveyed by means of a scraping member from the cooled wall into the suspension.
A coolable member (eg, a cooling stylus (cold stylus) installed by the crystallizer itself or in the crystallizer or other device.
It is also possible to produce crystals by cooling the melt or solution directly in the melt or solution by means of an inger), a cooling zone or a stirring vessel) and to produce a suspension in this way. This has the advantage that it is not necessary to scratch out the crystals. The use of coolable members is advantageous because it is not necessary to cool the entire crystallizer. It is also possible to produce the suspension in the crystallizer or externally and to precipitate the crystals of the suspension in the crystallizer on the crystallizing surface, where they act as seed crystals. The solid content of the suspension is 0-60 solids per gram of suspension.
g.
【００１５】本発明の有利な実施態様においては、結晶
器に懸濁液を充填し、引き続き結晶器を空にすることに
より結晶器表面に懸濁液を塗布する。空にした後で懸濁
層は結晶器表面に残留し、引き続き（その平衡温度で）
凍結する。懸濁液を結晶器自体で製造する場合は相当す
る方法を選択することができる。一般的な分配装置、た
とえば流出堰、ノズル、溝付き分配装置により、懸濁液
を結晶器表面に塗布することも可能である。これによ
り、装置の充填および引き続き空にすることの回避が可
能になる。In a preferred embodiment of the invention, the crystallizer is filled with the suspension and then the crystallizer surface is emptied by applying the suspension onto the crystallizer surface. After emptying, the suspended layer remains on the crystallizer surface and continues (at its equilibrium temperature)
to freeze. If the suspension is produced in the crystallizer itself, the corresponding method can be selected. It is also possible to apply the suspension to the crystallizer surface by means of customary distributors, for example outlet weirs, nozzles, grooved distributors. This makes it possible to avoid filling the device and subsequent emptying.
【００１６】本発明により適当な晶出を実施する方法
は、たとえば米国特許第５３２９０２１号明細書、ドイ
ツ特許第２６０６３６４号明細書およびドイツ特許第１
７６９１２３号明細書および欧州特許第０４７５８９３
号明細書に記載されている。本発明により、種結晶層を
塗布した後に精製すべき混合物を溶融物または溶液とし
て結晶器に導入し、引き続き固体の結晶相を結晶器の冷
却した表面に凍結する。晶出段階の開始時にすでに結晶
相が種結晶層として存在するので、精製すべき混合物は
もはや結晶を形成するために過冷却する必要がない。結
晶器を充填する間は、精製すべき溶融物または溶液は、
供給導管に結晶が形成されることを回避するために、融
点または融点よりわずかに高い摂氏温度で存在する。結
晶を懸濁液および凍結した固形物から沈殿した場合は、
粗製の溶融物または粗製の溶液を空にし、引き続き充填
することはもはや必要でない。この場合は直ちに晶出を
実施することができる。Methods for carrying out suitable crystallization according to the invention are described, for example, in US Pat. No. 5,329,021, German Patent 2,606,364 and German Patent No. 1.
769123 and EP 0475893.
It is described in the specification. According to the invention, after the seed crystal layer has been applied, the mixture to be purified is introduced into the crystallizer as a melt or solution and subsequently the solid crystalline phase is frozen on the cooled surface of the crystallizer. Since the crystalline phase is already present as a seed layer at the beginning of the crystallization stage, the mixture to be purified no longer needs to be supercooled to form crystals. While filling the crystallizer, the melt or solution to be purified is
It is present at or slightly above the melting point in degrees Celsius to avoid the formation of crystals in the feed conduit. If crystals were precipitated from suspension and frozen solids,
It is no longer necessary to empty and subsequently fill the crude melt or solution. In this case, crystallization can be carried out immediately.
【００１７】使用される一定の割合の混合物を凍結した
後で、２つの相を互いに分離し、これはたとえば液体残
留相を簡単に流出または排出することにより実施するこ
とができる。引き続き、分離した結晶相を結晶が液化す
る温度に加熱し、この溶融物または溶液を必要により、
ほかの晶出段階で処理する。残留相を以下に詳細に記載
されるほかの晶出段階で処理することも可能である。晶
出に続いてほかの精製段階を実施することができる。た
とえばドイツ特許出願公開第３７０８７０９号明細書に
記載される精製液を用いた結晶層の洗浄および／または
結晶層の発汗が特に適している。発汗中は結晶層の温度
が上昇し、結晶層のきわめて汚染された部分が溶離し、
こうして付加的な精製効果が達成される。After freezing the proportion of the mixture used, the two phases are separated from one another, which can be carried out, for example, by simply draining or draining the liquid residual phase. Subsequently, the separated crystal phase is heated to a temperature at which the crystals liquefy, and this melt or solution is added if necessary.
Process at another crystallization stage. It is also possible to treat the residual phase in other crystallization stages which are described in detail below. Other purification steps can be performed following crystallization. The cleaning of the crystal layer and / or the sweating of the crystal layer with the purification liquid described, for example, in DE-A-3708709 are particularly suitable. During sweating, the temperature of the crystal layer rises, the highly contaminated part of the crystal layer elutes,
In this way an additional refining effect is achieved.
【００１８】本発明の方法は、１つ以上の晶出段階で実
施する。一般に晶出段階を精製段階と追出段階に分ける
ことができる。分離効果を高めるために、晶出段階に続
いてほかの精製（晶出）段階を実施することができ、こ
のそれぞれにおいて先行する段階の結晶を晶出する。こ
の方法の収量を高めるために、追出段階を備えることが
可能であり、液体の残留相を追出（晶出）段階で処理す
る。この場合にこの方法は有利には向流原理にもとづ
き、結晶流を次の最も高い段数を有する段階に供給し、
晶出残留物流を次の最も低い段数を有する段階に供給す
る。晶出段階の数、従って精製および追出段階の数は分
離作業に依存し、当業者に周知の実験により決定するこ
とができる。The process of the invention is carried out in one or more crystallization stages. Generally, the crystallization stage can be divided into a purification stage and a drive-out stage. In order to enhance the separating effect, the crystallization step can be followed by another purification (crystallization) step, in each of which the crystals of the preceding step are crystallized. In order to increase the yield of this process, it is possible to provide an expulsion stage, in which the liquid residual phase is treated in the expulsion (crystallization) stage. In this case, the method is preferably based on the countercurrent principle, in which the crystal stream is fed to the next stage with the highest number of stages,
The crystallization residue stream is fed to the stage with the next lowest stage number. The number of crystallization steps, and thus the number of purification and drive steps, depends on the separation operation and can be determined by experiments well known to those skilled in the art.
【００１９】原則的に、前記方法で生じる任意の組成の
溶融物または溶液を懸濁液を製造するために使用するこ
とができる。本発明の有利な実施態様においては、懸濁
液を製造するために、個々の段階で晶出する溶融物また
は溶液より純粋の溶融物または溶液を使用する。有利に
は個々の晶出段階を離れる溶融結晶を使用する。In principle, melts or solutions of any composition which result from the process can be used to produce suspensions. In a preferred embodiment of the invention, a melt or solution that is purer than the melt or solution that crystallizes in the individual stages is used for producing the suspension. Preference is given to using molten crystals which leave the individual crystallization stages.
【００２０】[0020]
【実施例】本発明を以下の実施例により詳細に説明す
る。The present invention will be described in detail with reference to the following examples.
【００２１】例 最初の不純物含量０.６重量％（Ｎ−ビニルピロリドン
１００重量％に対して、この不純物濃度は米国特許第５
３２９０２１号明細書に記載の不純物濃度に相当する）
を有するＮ−ビニルピロリドンをドイツ特許出願公開第
２６０６３６４号明細書（ＢＡＳＦ）に記載の結晶器中
で、２つの精製段階および４つの追出段階で晶出した。
懸濁したＮ−ビニルピロリドン結晶を含有するＮ−ビニ
ルピロリドン溶融物からなる２相の懸濁液を、すべての
晶出段階で結晶器の表面に種結晶層として塗布した。種
結晶層を製造するために、個々の段階で結晶器に精製す
べき溶融物を充填し、装置を冷却することにより懸濁液
を製造した。引き続き装置を空にし、結晶器の表面に残
留する懸濁液を凝固した。個々の段階における晶出中の
溶融物の平衡温度は以下のとおりであった。EXAMPLE For an initial impurity content of 0.6% by weight (based on 100% by weight of N-vinylpyrrolidone, this impurity concentration is US Pat.
(Corresponding to the impurity concentration described in the specification of No. 390221)
N-vinylpyrrolidone having ## STR3 ## was crystallized in a crystallizer described in DE-A-2606364 (BASF) in two purification stages and four drive stages.
A two-phase suspension of N-vinylpyrrolidone melt containing suspended N-vinylpyrrolidone crystals was applied as a seed crystal layer on the surface of the crystallizer at all crystallization stages. To produce the seed crystal layer, a suspension was produced by filling the crystallizer with the melt to be purified in individual steps and cooling the apparatus. The device was then emptied and the suspension remaining on the surface of the crystallizer was solidified. The equilibrium temperatures of the melt during crystallization at the individual stages were as follows:
【００２２】精製段階５：１３.５〜１２.９℃ 精製段階６：１３.８〜１３.６℃ 追出段階１：１３.１〜１２.６℃ 追出段階２：１２.５〜１１.４℃ 追出段階３：１１.２〜８.５℃ 追出段階４：８.５〜４.３℃ 静的工程により作動した追出段階４を除いて、ほかのす
べての段階は動的工程により作動した。この段階で使用
される結晶の量に対する１つの段階で凍結した結晶の量
の比は、第１の精製段階で０.８であり、第２の精製段
階で０.７５であった。第１の精製段階においては結晶
中の０.１０２重量％の不純物濃度（Ｎ−ビニルピロリ
ドン１００重量％に対して）が達成された。前記の米国
特許明細書と比較して、これは１／４の不純物濃度に相
当する（不純物の濃度はＮ−ビニルピロリドン１００重
量％に対して０.４重量％であった）。引き続き結晶を
第２の精製段階に供給し、この段階を１９０ｐｐｍの不
純物濃度を有して離れ、これは不純物濃度が５００ｐｐ
ｍである前記の米国特許明細書と比較して約２.５分の
１である。Purification stage 5: 13.5 to 12.9 ° C. Purification stage 6: 13.8 to 13.6 ° C. Discharge stage 1: 13.1 to 12.6 ° C. Discharge stage 2: 12.5 to 11 ° .4 ° C. Ejection stage 3: 11.2-8.5 ° C. Ejection stage 4: 8.5-4.3 ° C. Except for the ejection stage 4 operated by the static process, all other stages are in motion. It operated by the automatic process. The ratio of the amount of crystals frozen in one stage to the amount of crystals used in this stage was 0.8 in the first purification stage and 0.75 in the second purification stage. In the first purification stage, an impurity concentration of 0.102% by weight in the crystals (based on 100% by weight of N-vinylpyrrolidone) was achieved. This corresponds to a concentration of impurities of 1/4 in comparison with the abovementioned U.S. patent specification (the concentration of impurities was 0.4% by weight, based on 100% by weight of N-vinylpyrrolidone). The crystals are subsequently fed to a second purification stage, which is left with an impurity concentration of 190 ppm, which has an impurity concentration of 500 pp.
m is about 2.5 times less than the above-mentioned U.S. patent specification.
【００２３】こうして、公知方法と比較して約２.５分
の１である、精製したＮ−ビニルピロリドン中の不純物
濃度が、本発明の方法により、同じ出発条件で、同じ数
の精製段階で、使用される溶融物または溶液に対して同
じ結晶凍結量で Ｎ−ビニルピロリドンの種結晶層を個
々の晶出の前に塗布することにより達成される。これは
同じ生成物特性で、少ない精製段階、従って必要な分離
経費のかなりの減少を示す。Thus, the impurity concentration in the purified N-vinylpyrrolidone, which is about 2.5 times less than the known method, is obtained by the method of the invention under the same starting conditions and the same number of purification steps. This is achieved by applying a seed crystal layer of N-vinylpyrrolidone with the same amount of crystal freezing to the melt or solution used before each crystallization. This shows the same product properties, fewer purification steps and thus a considerable reduction in the required separation costs.
Claims (1)
質を分離する方法において、分離すべき混合物の溶融物
または溶液と、これに懸濁している混合物の結晶とから
なる懸濁液の形の２相の種結晶層を、晶出の前に、晶出
中に結晶が成長する結晶器の表面に塗布することを特徴
とする、晶出により液体混合物から物質を分離する方
法。1. A method of separating substances from a liquid mixture by crystallization in a crystallizer, the form of a suspension comprising a melt or solution of the mixture to be separated and crystals of the mixture suspended therein. A method for separating substances from a liquid mixture by crystallization, characterized in that the two-phase seed crystal layer of 1. is applied to the surface of a crystallizer during which the crystals grow during crystallization, prior to crystallization.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19536792A DE19536792A1 (en) | 1995-10-02 | 1995-10-02 | Process for the separation of substances from a liquid mixture by crystallization |
| DE19536792.8 | 1995-10-02 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09103604A true JPH09103604A (en) | 1997-04-22 |
| JP4092738B2 JP4092738B2 (en) | 2008-05-28 |
Family
ID=7773896
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25941896A Expired - Fee Related JP4092738B2 (en) | 1995-10-02 | 1996-09-30 | Method for separating a substance from a liquid mixture by crystallization |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5755975A (en) |
| EP (1) | EP0766984B1 (en) |
| JP (1) | JP4092738B2 (en) |
| CN (1) | CN1083283C (en) |
| DE (2) | DE19536792A1 (en) |
| ES (1) | ES2126358T3 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008523005A (en) * | 2004-12-07 | 2008-07-03 | ビーエーエスエフ ソシエタス・ヨーロピア | Purification of ionic liquid |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10101611A (en) * | 1996-09-30 | 1998-04-21 | Nippon Steel Chem Co Ltd | Purification of benzoic acid |
| DE19904820A1 (en) * | 1999-02-05 | 2000-08-10 | Stockhausen Chem Fab Gmbh | Method and device for cleaning substances by means of crystallization |
| DE10103208A1 (en) * | 2001-01-24 | 2002-08-14 | Ruetgers Vft Ag | Obtaining anthracene and carbazole by melt crystallization |
| US7189328B1 (en) * | 2004-06-25 | 2007-03-13 | Eau-Viron Incorporated | Method for extraction of dissolved trace materials from solution |
| DE102004038107A1 (en) | 2004-08-05 | 2006-03-16 | Basf Ag | Process for improving the color stability of piperazine |
| US7138528B2 (en) * | 2005-02-01 | 2006-11-21 | Lyondell Chemical Technology, L.P. | Method for crystallizing N-vinyl-2-pyrrolidone |
| CN100338021C (en) * | 2006-06-19 | 2007-09-19 | 常州市佳森化工有限公司 | Crystallizing separating tech. of nitro methyl-phenoxide mixture |
| JP2011201865A (en) * | 2010-03-02 | 2011-10-13 | Sumitomo Chemical Co Ltd | METHOD FOR PRODUCING epsi-CAPROLACTAM |
| US9120743B2 (en) | 2013-06-27 | 2015-09-01 | Celanese International Corporation | Integrated process for the production of acrylic acids and acrylates |
| PL3119489T3 (en) * | 2014-03-19 | 2022-01-17 | Basf Se | Method for separating a substance from a solution |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT279547B (en) * | 1967-04-14 | 1970-03-10 | Buchs Metallwerk Ag | Method and device for separating or purifying molten, liquid or dissolved substances by fractional crystallization |
| US4004886A (en) * | 1969-12-12 | 1977-01-25 | Stamicarbon B.V. | Two stage continuous process and apparatus for crystallization |
| US3844724A (en) * | 1971-12-27 | 1974-10-29 | Du Pont | Zone-melting apparatus |
| DE2606364B2 (en) * | 1976-02-18 | 1981-07-30 | Basf Ag, 6700 Ludwigshafen | Process for the separation of substances from a liquid mixture by fractional crystallization |
| US4199373A (en) * | 1979-04-13 | 1980-04-22 | Chimicasa Gmbh | Process for the manufacture of crystalline fructose |
| DE3203818A1 (en) * | 1982-02-04 | 1983-08-11 | Rütgerswerke AG, 6000 Frankfurt | METHOD AND DEVICE FOR SEPARATING A LIQUID MIXTURE BY FRACTIONATED CRYSTALIZATION |
| US4657559A (en) * | 1985-05-08 | 1987-04-14 | Freeport Research And Engineering Company | Process for seed crystal preparation for phosphoric acid crystallization |
| CH667816A5 (en) * | 1985-10-09 | 1988-11-15 | Sulzer Ag | CRYSTALIZATION DEVICE AND THEIR USE. |
| US4795571A (en) * | 1987-02-20 | 1989-01-03 | Basf Aktiengesellschaft | Purification of frozen crystal layers |
| DE3708709A1 (en) * | 1987-03-18 | 1988-10-06 | Basf Ag | Process for the purification of frozen-out crystal layers |
| US4787985A (en) * | 1987-08-25 | 1988-11-29 | Grenco Process Technology B.V. | Multi-stage purification unit process |
| DK0480519T3 (en) * | 1990-10-12 | 1996-06-24 | Duphar Int Res | Solid lactulose |
| US5329021A (en) * | 1993-02-04 | 1994-07-12 | Isp Investments Inc. | Process for the production of pure vinyl pyrrolidone |
| US5434316A (en) * | 1994-07-28 | 1995-07-18 | General Electric Company | Purification of bisphenol-A |
-
1995
- 1995-10-02 DE DE19536792A patent/DE19536792A1/en not_active Withdrawn
-
1996
- 1996-09-09 US US08/708,821 patent/US5755975A/en not_active Expired - Lifetime
- 1996-09-27 CN CN96113058A patent/CN1083283C/en not_active Expired - Fee Related
- 1996-09-30 JP JP25941896A patent/JP4092738B2/en not_active Expired - Fee Related
- 1996-10-02 ES ES96115817T patent/ES2126358T3/en not_active Expired - Lifetime
- 1996-10-02 EP EP96115817A patent/EP0766984B1/en not_active Expired - Lifetime
- 1996-10-02 DE DE59601069T patent/DE59601069D1/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008523005A (en) * | 2004-12-07 | 2008-07-03 | ビーエーエスエフ ソシエタス・ヨーロピア | Purification of ionic liquid |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0766984B1 (en) | 1998-12-30 |
| DE19536792A1 (en) | 1997-04-03 |
| ES2126358T3 (en) | 1999-03-16 |
| DE59601069D1 (en) | 1999-02-11 |
| CN1083283C (en) | 2002-04-24 |
| US5755975A (en) | 1998-05-26 |
| JP4092738B2 (en) | 2008-05-28 |
| EP0766984A1 (en) | 1997-04-09 |
| CN1151329A (en) | 1997-06-11 |
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